GHRP-6

Scientific identity. GHRP-6 is a synthetic hexapeptide with the sequence His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂. It contains two D-amino acid residues — D-tryptophan at position 2 and D-phenylalanine at position 5 — which contribute to GHSR-1a binding affinity and resistance to proteolytic degradation relative to all-L peptide analogues. The C-terminal lysine amide is required for full receptor activity. GHRP-6 was developed from systematic structure-activity research on enkephalin analogues — its design origin as an opioid receptor ligand analogue distinguishes it historically from GHRH-derived peptides, though its primary pharmacological activity in research is at GHSR-1a rather than opioid receptors.

Peptide class. Synthetic hexapeptide; growth hormone secretagogue (GHS); ghrelin receptor (GHSR-1a) agonist; GH-releasing peptide family member.

Primary receptor target. GHSR-1a (growth hormone secretagogue receptor type 1a) — a class A G protein-coupled receptor and the endogenous receptor for ghrelin. GHSR-1a is expressed in the pituitary, hypothalamus, and multiple peripheral tissues. Activation of GHSR-1a in pituitary somatotrophs stimulates GH secretion through Gαq/11-coupled signaling, distinguishing the GHSR-1a mechanism from the Gαs-coupled cAMP pathway activated by GHRHR agonists.

Research areas. GHSR-1a pharmacology, ghrelin receptor biology, pulsatile GH secretion research, pituitary somatotroph biology, GH secretagogue structure-activity research, GH/IGF-1 axis research, appetite and energy homeostasis research models, comparative GH secretagogue pharmacology.

Product quantity. 10mg per vial.

Physical form. Supplied as a lyophilised solid in a sealed research vial.

Purity. Greater than 99%, confirmed by HPLC and LC-MS analysis at the batch level.

Analytical documentation. A batch-specific Certificate of Analysis is available on the Longevia Research website, covering compound identity, purity, and lot traceability.

Research-use classification. For laboratory research use only. Not for human or veterinary use, clinical diagnostics, or any in-vivo application in humans.

GHSR-1a and Ghrelin Receptor Biology

GHSR-1a is a class A GPCR and the endogenous receptor for ghrelin — a 28-amino-acid acylated peptide hormone secreted primarily from gastric X/A-like cells. Unlike GHRHR — which is coupled to Gαs and signals through cAMP — GHSR-1a couples primarily to Gαq/11, activating phospholipase C, IP₃ production, and intracellular calcium mobilisation in pituitary somatotroph cells to stimulate GH secretion. GHSR-1a also exhibits constitutive activity — a high level of receptor activation in the absence of ligand — that is studied in GPCR pharmacology as a model of constitutively active receptor behaviour. GHRP-6 was one of the first synthetic ligands used to characterise this receptor system and remains a reference compound in GHSR-1a pharmacology research.

Distinction from GHRH Receptor Agonists

GHRP-6 and GHRH analogues (CJC-1295 No DAC, Sermorelin, Tesamorelin) both stimulate GH secretion from pituitary somatotrophs in experimental systems but through entirely separate receptor systems. GHRHR agonists activate the Gαs/cAMP/PKA pathway; GHSR-1a agonists activate the Gαq/11/PLC/calcium pathway. Research examining the combined effect of GHRHR and GHSR-1a co-activation — using GHRH analogues and GH secretagogues in parallel — has characterised synergistic GH release in animal models, reflecting the two pathways' complementary signaling mechanisms. This makes GHRP-6 a research tool distinct from and complementary to the GHRH analogue series.

GH Secretagogue Family and Selectivity Research

GHRP-6 belongs to the first generation of synthetic GH secretagogues alongside GHRP-2. Both are hexapeptides with D-amino acid substitutions and C-terminal amides, but differ in sequence and receptor activity profile. GHRP-6 engages GHSR-1a with high affinity and also has measurable activity at other receptors — including the CD36 scavenger receptor and cortistatin/ghrelin receptor subtypes — in defined experimental systems. Ipamorelin, developed later, was engineered for improved GHSR-1a selectivity over GHRP-6 and GHRP-2, making the three compounds useful comparative tools in GHSR-1a selectivity research.

Appetite and Energy Homeostasis Research

GHSR-1a expression in the hypothalamus — particularly the arcuate nucleus — has motivated research into ghrelin receptor agonist effects on appetite signaling and energy homeostasis alongside GH secretion. Animal studies have examined GHRP-6 in feeding behavior and energy expenditure models, reflecting GHSR-1a's established role in appetite regulation. These findings are model-specific preclinical observations in defined animal experimental systems.

Research Status

GHRP-6 has no regulatory approval for any therapeutic indication in any jurisdiction. It has been extensively used as a preclinical research tool in GHSR-1a pharmacology and GH secretagogue research. No approved pharmaceutical formulation of GHRP-6 exists. It is supplied for Research Use Only.

Reliable research begins with accurately characterised material. For a hexapeptide containing D-amino acid residues such as GHRP-6, that means confirming sequence integrity — including correct D-configuration at Trp² and Phe⁵ — and purity at the batch level. Epimerisation of D-amino acids to L-configuration produces structurally distinct diastereomers that may co-elute with the authentic compound under some chromatographic conditions but carry substantially different GHSR-1a binding affinities, directly confounding receptor pharmacology assays.

Purity assessment. Each production lot is characterised to greater than 99% purity by high-performance liquid chromatography (HPLC). Chromatographic purity data is reported on the batch Certificate of Analysis.

Identity confirmation. Peptide identity, D-amino acid configuration, and C-terminal amide are confirmed by mass spectrometry (LC-MS), providing molecular-weight verification consistent with the specified hexapeptide. HPLC and LC-MS data together confirm that the material supplied corresponds to the labelled compound at the labelled purity.

Batch traceability and Certificate of Analysis. Every vial of GHRP-6 10mg is traceable to a specific production lot. A batch-specific Certificate of Analysis is accessible directly on the Longevia Research website, covering purity, identity, and lot information. Researchers evaluating this material for assay work are encouraged to review the current batch documentation before use, since analytical specifications are applied at the lot level.

Handling. This material should be handled by qualified personnel using appropriate laboratory technique and personal protective equipment, consistent with institutional protocols for research-grade synthetic peptides containing D-amino acid residues.

Longevia Research supplies GHRP-6 10mg for laboratory and in-vitro research use only. The product is intended for use by qualified researchers and trained laboratory personnel in appropriate controlled research environments.

GHRP-6 is a synthetic research peptide supplied strictly as a research tool. It is not a drug, not a dietary supplement, not a food or food ingredient, and not a cosmetic. No regulatory authority has approved GHRP-6 for any human or veterinary therapeutic use, and Longevia does not supply it for administration to humans or animals, for clinical diagnostics, or for any therapeutic purpose.

Longevia provides no dosing instructions, administration guidance, treatment protocols, or reconstitution recommendations for this compound. The scientific literature summarised on this product page describes experimental observations in defined cell-based and animal model systems. Those findings are not medical claims and should not be interpreted as evidence of human efficacy, human safety, or fitness for any clinical application.

The purchaser assumes full responsibility for lawful acquisition, handling, storage, use, and disposal of this material, and for compliance with all applicable local, state, federal, and institutional regulations. By purchasing this product, the buyer confirms that it will be used solely for legitimate laboratory research purposes by qualified personnel, and that its acquisition and intended use comply with applicable laws in the buyer's jurisdiction.